Art of dehydrating fibers with lubricating and antistatic coatings



Jan. 5, 1965 3,164,650

W. R. KOCAY ETAL ART OF DEHYDRATING FIBERS WITH LUBRICATING AND ANTI-STATIC COATINGS Filed Dec. 18, 1961 ANT/STATIC AGE/VT 24 LUBRICANT INVENTORS. W/TOLD R. KOCAY ALFRED G. COMOLL/ uUH/V A. Mc/(EE United States. Patent 3,164,650 ART OF DEHYDRATIN G FIBERS WITH LUBRICAT- ING AND ANTISTATIC COATINGS Witold Roman Kooay, Stamford, Alfred George Comolli, Greenwich, and John Andrew McKee, Norwalk, Conn., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine Filed Dec. 18, 1%1, Ser. No. 159,946 7 Claims. (Cl. 26413tl) This invention relates to new and useful improvements in the art of dehydrating shaped articles or structures, e.g., films, ribbons, tapes, filaments, etc. of organic materials and, more particularly, for dehydrating shaped articles from polymeric materials, such as, for example, an acrylonitrile polymerization product. In a presently preferred form, this invention relates to improvement in dehydrating endless filaments of acrylonitrile polymers and the application thereto of materials having anti-static properties.

Shaped articles may be made from many polymeric materials by processes which involve the dehydration of uncollapsed structures to produce collapsed structures. By uncollapsed structures is meant porous structures of relatively low density and by collapsed structures is meant nonporous structures of relatively high density. Among these processes may be mentioned wet spinning lubricating and l wherein a polymer solution is extruded into a liquid coagulating medium to produce a wet shaped article having an uncollapsed structure which must subsequently be dehydrated and collapsed and dry spinning wherein a polymer solution in a volatile solvent is extruded into a gaseous coagulating medium into which solvent can evaporate to produce a shaped article having an uncollapsed structure which is subsequently washed (to free it of solvent) followed by dehydration and collapse thereof.

Many currently known polymeric materials are known to be formable into shaped articles by such processes.

Among such materials may be mentioned polyamides, e.g., nylon; polyesters, e.g., poly(ethylene glycol terephthalate); vinyl polymers, e.g., polyvinyl chloride, polyvinyl alcohol; and acrylic polymers, e.g.,- polyacrylonitrile as well as copolymers of acrylonitrile and one or more other vinyl monomers. Suitablelsolvents for these materials are Well known for use in wet spinning and/ or. dry spinning processes. This invention, while useful for the dehydration and collapse of shaped articles of such materials, was particularly developed in connection with the dehydration and collapse of shaped articles in the form of filaments of acrylonitrile polymers. To simplify the further explanation, the dehydration and collapse of wetspun filaments of acrylonitrile polymers will be utilized to illustrate this invention with the understanding that this invention is not limited thereto.

Various processes for preparing shaped articles from acrylonitrile polymers are known and described in the literature. In these processes, acrylonitrile polymers are dissolved in a suitable solvent and extruded through a spinnerette into a coagulating medium to form the shaped articles in a wet gel state. The wet gel structures after elongation, if desired, are then dehydrated to collapse the .gel structure, and the dehydrated collapsed shaped structures are then subjected to such further treatment as may be necessary or desirable to improve the properties of such shaped structures and/ or to convert such shaped structures into useful final products; For this purpose, it is usually advisable to apply to the shaped articles suitable lubricants and anti static agents.

It has been known to apply to the met gel structure, prior to dehydration and collapse, materials havinglubricant and anti-static properties (either as a single matc- 3,164,65fi Patented Jan. 5, 1965 rial having both properties or as a mixture of materials separately having such properties). We have found that this is unsatisfactory when applied to shaped articles, such as endless filaments of acrylonitrile polymers, which require relatively high temperatures to dehydrate them in the relatively short time available in high speed production utilizing heated thread-advancing rolls for such dehydration. Among these disadvantages may be mentioned discoloration of the yarn and variable light scatter in the yarn produced if the temperature in such rolls is maintained high enough to satisfactorily dehydrate such polymer. Alternatively, if the temperatures are maintained low enough to avoid the color and light-scatter problems, satisfactory dehydration of the gel structure is not achieved.

It is likewise unsatisfactory where such materials having anti-static properties and lubricant properties are applied to the dehydrated, collapsed structure after such heated thread-advancing rolls. With the rolls at a temperature high enough to satisfactorily dehydrate the wet gel structure, operabili-ty of the dehydration step is very poor to inoperable producing, in either event, shaped articles, such as filaments, which are commercially useless due to severe degradation of the physical properties.

The present invention is based on our discovcry that the above difficulties can be overcome and other useful advantages and further improvements in the product produced can be achieved if, prior to collapse of the wet gel structure, a lubricant isapplied to the wet gel structure, andsubsequent to such collapse, an anti-static agent is applied to the dehydrated, collapsed structure. Where such anti-static agent is appied as an aqueous dispersion thereof, advantageously, it may be dried quickly without subjecting the anti-static agent to the prolonged exposure to high temperatures needed for dehydration of the gel structure.

For a better understanding of this invention, reference may be had to the subjoined description read in conjunction with the accompanying drawing, the sole figure of which is a schematic illustration of the several steps involved in the method of the invention as utilized in the dehydration of shaped articles in the form of filaments and indicative'of apparatus that can be used in practicing the method.

Endless filaments 16 having a wet gel structure are drawn past a lubricator 24 to heated thread-advancing rolls 25. On rolls 25, the filaments 16 advance from the left side toward the right as seen in the drawing while they are dehydrated and the filament structure is collapsed. When the filaments have become substantially dehydrated and collapsed, they are withdrawn from the thread-advancing rolls 25, guided past applicator 26, which provides an anti-static finish to the thread, around guide roll 27, and then back around a remaining portion 25a of heated thread-advancing rolls 25 for drying the anti-static finish thereon. From portion 251: of heated thread-advancing rolls 25, endless filaments 28 having a dehydrated collapsed structure and suitably provided with lubricants and antistatic agents thereon may be passed through such additional treatment stages as may be necessary or desirable prior to collection of such filaments as final product.

To provide a greater understanding of this invention, and the objects and advantages thereof, a presently preferred embodiment of the invention will now be described to illustrate this invention in greater detail.

' It is to be expressly understood, however, that the. following detailsare to be considered as illustrative only contained inthe claims themselves.

' This invention was particularly developed for process iug polymers formed by the spinning of'solutions of acrylonitrile polymers in a suitable solvent. Many such spinning solutions containing acrylonitrile polymerization products are known and are useful for this invention.

Typical of such polymers and solvents are those disclosed in Cummings U.S. Patent No. 2,948,581 dated .August 9, 1960, and the various other U.S. patents mentioned therein.

Representative compounds which may be polymerized with acrylonitrile to form acryloni-trile polymerization products useful for the practice of thisinvention are compounds containing a single CH C grouping, for instance, the vinyl esters and especially the vinyl esters of saturated aliphatic monocarboxylic acids, e.g., vinyl acetate, .vinyl propionate, vinyl butyrate, etc., vinyl and vinylidene halides, e.g., the vinyl and vinylidene chlorides, bromides and fluorides; allyl-type alcohols, e.g., allyl alcohol, methallyl. alcohol, ,ethallyl alcohol, etc.; allyl, methllyl and other unsaturated monohydric alcohol esters of-monobasic acids, e.g., allyl and methallyl acetates, laurates, cyanides, etc; acrylic and alkacrylic acids (e.g., methacrylic, ethacrylic, etc.) and esters and amides of such acids (e.g., methyl, ethyl, propyl, butyl, etc., acrylatcs and methacrylates, acrylamide, rnethacrylamide, N- methyl, ethyl, propyl, butyl, etc., acrylamides and methacrylamides, etc); :methacrylonitrile, ethacrylonitrile and other hydrocarbon-substituted acrylonitriles; unsaturated aliphatic hydrocarbons containing a single CH =C grouping, e.g., isobutylene,etc.; and numerous other vinyl,

'acrylic and other compounds containing a single grouping which are copolymerizable with acrylonitrile to yield thermoplastic copolyme'rs. Alkyl esters of-alpha, beta-unsaturated polycarboxylic acids may also be .co-

the order of 50,000 to 100,000, e.g., about 70,00080,000,

as calculated from a viscosity measurement of'the said polymerization product in dimethylformamide usingthe Staudinger equation (reference: Houtz U.S. Patent No. 2,404,713, dated July 23, 1946).

While it is preferred-to have the polymer molecule contain at least about 80% combined acrylonitrile, it is to be1understood that polymers containing less than this Lubricator 24 may be of any conventional design, and preferablyof the kiss roll type wherein a slowly rotating roll partially immersed in lubricant contained in a trough transfers lubricant' t o filaments 16 by direct contact therewith.

Heated. thread advancing rolls may be of, the types shown in Forzley et al. U.S. Patent No. 2,622,182 dated December 16, 1952 or Bundegaard et al. U.S. Patent No. 2,777,931 dated January 15, 1957. it will be noted that part way across the length of heated thread-advancing rolls 25, afterfilarnents 16 have been dehydrated and the gel structure collapsed, filaments 16 are led off rolls 25, past applicator 26, around guide 2'7, and back around end portions 25a of rolls 25 for a few'more turns. Applicator 26 may be of any conventional design and is preferably of the k'ss roll type similar to lubricator 24.

Lubricator 24' applies to the wet gel filaments 16 a lubricant coating to protect the thread 16 during the drying operation. Applicator 26 applies to the dehydrated collapsed filaments 28 an anti-static coating from an aqueous dispersion thereof. This application to the thread 7 of the lubricant and the anti-static agent at separated 1ocations is important to achieve optimum utilization of these compounds. It has been found that the anti-static agent tends to be adversely affected by'prolonged exposure to heat and also that it is essential that the thread be protected for the full time it is exposed to the heat from thread advancing rolls 26; Accordingly, it was found that this could bestbe accomplished by lubricating the thread with a suitable lubricant such as, for example, an

ethylene oxide condensate of castor oil, prior to collapsing the fiber structure and then applying an anti-static agent such as, for example, stearamidopropyl li-hydroxyethyl dir'nethyl ammonium dihydrogen phosphate to the dehydrated, collapsed structure from an aqueous disper sion thereof, folowed by a rapid drying merely of the surface moisture-introduced by the anti-static, addition.

in addition to the above-named lubricant, numerous other suitable lubricants arelrnown and are satisfactory for the pratcice of this invention. Such lubricants include mineral, vegetable, and animal oils, among which latter may be mentioned blown. and unblown neats foot oil, sperm oil, olive oil, castor oil, teaseed oil, peanut oil,

soya bean oil and cottonseed oil, as well as the various the antistatic agent are Wetting and dispersing agents, as

amount of acrylonitrile may also be useful for the prac:

well as other effect agents, including, for example, N-octadecyl disodium sulfosuccinamate, dioctyl sodium sulfosuccinate, lecithin, esters of long-chain fatty acids, e.g., alkyl stearates, palmitates and oleates, more particularly the ethyl, propyl, butyl and amyl stearates, palmitates and oleates, as Well as hydroxyethylated estersand amides of long-chain fatty acids. 7

In addition to the abovenamed anti-static agent, numerous other suitable anti-static agents are known and may be used in the practice of this invention. Such anti-static agents include surface-active quaternary ammonium compounds, such as phenylguanidine stearate; guanylurea and guanidine salts, e.g., guanylurea octadecyl hydrogen sulfate, guanidine octadecyl hydrogen sulfate, guanidine v oleyl. hydrogen sulfate; allroxy-propionitriles, e.g., octadissolved in a concentrated aqueous solution of sodium thiocyanate and was spun 'in'to coagulating bath comprising a cold dilute aqueous solution of sodium thiocyanateto form endless'filaments. These filaments were 'then washed substantially free of salts and elongated in heated aqueous baths to'produce the uncollapsed wet gel decoxy propionitriles; reaction products of ethylene oxide and a long-chain alkyl guanamine or guanadine, e.g., octadecyl guanamine, octadecyl guanidine; the compounds listed in Games, U.S. Patent Nos. 2,626,876 and 2,626,- 877, both dated January 27, 1953; and sulfosuccinate salts listed in Games et a1. U.S. Patent No. 2,652,348 dated September'lS, 1953. i 3

Surprisingly, it was found that a major cause of variability in the luster of the finished product after washing or scouring was attributable to the mode of addition of the. anti-static agent. When the anti-static agent is ap- 'j,,;ant heaters external to such rolls and directedthereon.

plied to the fiber in the wet gel state, there is a highly variable penetration of the anti-static agent into the structure of the fiber which results in producinga variable luster in the ultimate product. However, if the anti-static possibly make the difference between commercial utility and lack of commercial acceptance of the final product.

In order to completely dehydrate. and collapse the structure in contact with the hot surface of rolls 25, it is essential to protect the surface of the filaments. Failure to supply a non-volatile protective lubricant results in the filaments tending to fuse and stick to the surfaces of the rolls after the surface moisture is removed and before the moisture in the interior of the wet gel structure is completely gone. of the skin of the filaments resulting in greatly reduced fiber strength. The lubricant coating, however, prevents the filaments from sticking to the hot surfaces of the heated rolls 25 after the surface moisture is removed and while the interior moisture isbeing removed during collapsing of the gel structure. Thus, it is essential that the lubricant be applied prior to collapse of the fiber structure.

This sticking produces a splitting Also, failure to apply lubricant to the filaments prior to collapse thereof results in a splaying 'or spreading out of the individual filaments from each other causing filaments to overlap eachfother from one wrapto the next. On the last portion a of heated thread-advancing rolls 25, the filaments 28 are quickly heated to dry them by the removal of surface moisture therefrom, such surface moisture resulting from the application of the antistatic agent asan aqueous dispersion thereof. While the term aqueous dispersion is intended to inplude solutions or suspensions or colloids of the anti-static agents in Water, dispersions in other media than water may also be used.

, ,In such event, portion 25aserves todry the filaments 28 by evaporationofsuch media.

As indicated before, heated thread advancing rollsrmay be of the type shown in theabove-m'entioned Forzley et al. or Bundegaard et al. US. patents. "In. .the practice of this invention, it was'found perferable that such rolls have a heat-conducting surface, suchas of a metal or alloy resistant to corrosion by" the, materials contacting it.

' -While it is preferred to hejat such rolls by use of electrical elements inside them, it is to be under'stoodithat other conventional meansi ,may be used, such as superheated steam or hot gases introducedto withinthe rolls or radi- As a specific example, polyacrylonitrile'ffilaments have been dehydrated and provided with adethylerie oxide condensate of 'castor Oil lubricant and stearamidopropyl fl-hydroxyethyl dimethyl ammonium dihydroge 'n phosing electrically heated metal surfaced thread-advancing such heated rolls, the surface of which is moved at the same speed as the thread in contact therewith, for a period of between 0.5 andlS seconds, and preferably between about 1 and 10 seconds.

We claim:

1. In the process of producing shaped articles from polymerization products which includes the formation of a wet uncollapsed structure, and the subsequent dehydration of such structure in contact with a moving heated'surface, the improvement comprising: lubricating said wet. uncollapsed structure with a lubricant; dehydrating said wet uncollapsed structure in contact with a moving heated surface with the lubricant thereon to produce a collapsed polymer structure; and applying an antistatic agent to said collapsed polymer structure.

2. A process as defined in claim 1 wherein said shaped articles comprise endless filaments of an acrylonitrile polymerization product.

3. In the process of producing shaped articles from an acrylonitrile polymerization product which includes the formation of a wet gel'structure, and the subsequent dehydration of such structure in contact with a moving heated surface, the improvement comprising: lubricating said wet gel structure with a lubricant; dehydrating said wet gel structure in contact with a moving heated surface with the lubricant thereon to produce a collapsed polymer structure; applying an anti-static agent as an aqueous dispersion to said collapsed polymer structure; and drying said collapsed polymer structure with the antistatic agent thereon.

4. In the process of producing shaped articles from polymerization products which includes the formation of a Wet uncollapsed structure, and the subsequent deh dration of such structure, the improvement comprising: lubricating said wet uncollapsed structure with a lubrij cant; dehydrating said wet uncollapsed structure with the plying an anti-static agent as a dispersion to said co1-' lapsed polymer structure; and drying said collapsed'polylubricant thereon in contact with a heated moving metal surface to produce a collapsed polymerstructure; ap-

mer structurewith theanti-static agent thereone 5, A process as defined in claim 4 wherein said shaped articles comprise endless filaments of an acrylonitrile -po- :lymerization product. i 1

moving metal surface is moved at the same speed as the yrolls at atemperature of between about 10Q. .F. a nd 550 F., and preferably between about lSO'QFfto about 450 F., while maintainingthe-thread in contact with acrylonitrile polymerization product in contact therewith,

said speedbeing in excess of 200 meters per minute.

References Cited in the fileof this patent p UNITED STATES PATENTS 2,1 6,135

I Childs Jan. 9, .1940

- 2,558,731 Cresswell L July 3,1951 2,614,289 Cresswell- Oct. 2l, 1952 2,869,972. Head :Jan.' 20,1959

=3;052,512 Kocayn Sept- 4, 1962 Oldershaw Aug. 13, 1963 

1. IN THE PROCESS OF PRODUCING SHAPED ARTICLES FROM POLYMERIZATION PRODUCTS WHICH INCLUDES THE FORMATION OF A WET UNCOLLAPSED STRUCTURE, AND THE SUBSEQUENT DEHYDRATION OF SUCH STRUCTURE IN CONTACT WITH A MOVING HEATED SURFACE, THE IMPROVEMENT COMPRISING: LUBRICATING SAID WET UNCOLLAPSED STRUCTURE WITH A LUBRICANT; DEHYDRATING SAID WET UNCOLLAPSED STRUCTURE IN CONTACT WITH A MOVING HEATED SURFACE WITH THE LUBRICANT THEREON TO PRODUCE A COLLAPSED POLYMER STRUCTURE; AND APPLYING AN ANTISTATIC AGENT TO SAID COLLAPSED POLYMER STRUCTURE. 